求和两列，计算 MapReduce 中的最大值、最小值和平均值

Question

I have a sample code of mapper as the following shows, the key is UCO, the value is TaxiTotal, which should be the sum of two columns, TaxiIn and TaxiOut, how to sum the two columns?

my current solution TaxiIn + TaxiOut result in a paste number, like 333+444 = 333444, I need it to be 777， how to write the code?

#! /usr/bin/env python

import sys

# -- Airline Data
# Year, Month, DayofMonth, DayOfWeek, DepTime, CRSDepTime, ArrTime, CRSArrTime, UniqueCarrier, FlightNum,
# TailNum, ActualElapsedTime, CRSElapsedTime, AirTime, ArrDelay, DepDelay, Origin, Dest,         Distance, TaxiIn,
# TaxiOut, Cancelled, CancellationCode, Diverted, CarrierDelay, WeatherDelay, NASDelay, SecurityDelay, LateAircraftDelay

for line in sys.stdin:
    line = line.strip()
    unpacked = line.split(",")
    Year, Month, DayofMonth, DayOfWeek, DepTime, CRSDepTime, ArrTime, CRSArrTime, UniqueCarrier, FlightNum, TailNum, ActualElapsedTime, CRSElapsedTime, AirTime, ArrDelay, DepDelay, Origin, Dest, Distance, TaxiIn,TaxiOut, Cancelled, CancellationCode, Diverted, CarrierDelay, WeatherDelay, NASDelay, SecurityDelay, LateAircraftDelay = line.split(",")
    UCO = "-".join([UniqueCarrier, Origin])
    results = [UCO, TaxiIn+TaxiOut]
    print("\t".join(results))

Answer 1

Convert TaxiIn + TaxiOut to:

int(TaxiIn) + int(TaxiOut)

See below example:

In [1612]: TaxiIn = '333'                                                                                                                                                                                   

In [1613]: TaxiOut = '444'                                                                                                                                                                                  

In [1614]: TaxiIn + TaxiOut                                                                                                                                                                                 
Out[1614]: '333444'

In [1615]: int(TaxiIn) + int(TaxiOut)                                                                                                                                                                       
Out[1615]: 777

You can't have numerical sums of string, for that convert str to int or float .

your code should be:

results = [UCO, str(int(TaxiIn) + int(TaxiOut))]
print("\t".join(results))